1. Field of the Invention
The present invention relates to processes and systems for decontamination of soils, and more particularly relates to methods and systems for decontamination of poly chlorinated biphenyl contaminated soils.
2. Description of the Related Art
The problem of poly chlorinated biphenyl (PCB) pollution of soils has been a major concern for some time. Accidental spills and improper land use have left numerous sites across the United States with PCB contaminated soil sites.
Various approaches have been used in efforts to decontaminate polychlorinated biphenyl laden soils. Efforts have included in-situ bio-destruction, thermal desorption, chemical declorination/destruction, and solvent extraction and soil washing. Solvent extraction processes have usually suffered from one or more of the following problems: environment impact of the solvent, lack of efficiency in movement of the contaminant from the soil to the solvent, difficulty of removal of solvent from the soil, solvent expense, and/or difficulty of separation of solvent from the contaminate. Specific decontamination methods are disclosed in Sivavec, Decontamination of Soil and Other Particulate Matter, U.S. Pat. No. 5,427,688 Jun. 27, 1995, and Szejtli et al. Method for the Extraction of Organic Pollutants from Contaminated Soils, U.S. Pat. No. 5,425,881 issued Jun. 20, 1995, which are both incorporated herein by reference.
Consequently, there is a need for a method and apparatus (system) that solves the above problems and provides for efficient removal of polychlorinated biphenyls from soil.